Oil for withstanding high bearing pressures and method of making the same



r from the following description. Its viscosity mayvary considerably,depending Patented-June 21, 1938 I UNITEDSTATES PATENT OFFICE OIL FORWITHSTANDING HIGH BEARING- PRESSURES. AND METHOD OF MAKHWG THE SAME iCharles B. Karns, Pittsburgh, Pa., assignor to Standard Oil DevelopmentCompany, a corporation of Delaware No Drawing. Application May 2, 1934,

Serial No. 723,505

20 Claims. (Cb 87-9) The present invention relates to improved and whichmay be characterized by Viscosity lubricating oils, especially to oilsof high quality- Indices well above 100. and capable of withstandinghigh bearing pres- The oil which is selected for the present pursures.The invention will be fully understood pose should be of good color andwell refined.

Leaded or lead-containing oils have been used upon the s'ervice'f orwhich the oil is destined. for a considerable period of time because oftheir For some purposes a viscosity from 50 to 60 ability to withstandheavy loads and leadoleate seconds Saybolt at 210 F. to 80 or 90 issatisfacis the most generally used substance employed in tory, but forgear or transmission oils for heavier e their manufacture.Unfortunately, lead oleate service higher viscosities are desirable, sayabove 10 and the lead salts of most of the similar fatty 100 or 120 at210 F., and they may be as high acids are not freely soluble in highgrade lubrias 200 or 250 for particularly heavy duty. The eating allbases, such as cylinder oils, bright stocks base oil is first subjectedto a mild oxidation and the like, derived from wax bearing crudes.treatment which is preferably carried out by On standing for arelatively short time the lead bubbling air or other oxidizing gasthrough the 15 compound is observed to settle from the oil in a oil,while maintained at a temperature of the thick sludge. The lower gradebase oils, howorder of 400 to 450 F. The time required for ever, arecapable of maintaining the oil in a the treatment depends on thetemperature and stable form and it is for this reason that such the rateof air flow, and the conditions may be of leaded lubricants. to whichthe lead may be added in a stable form.

The low grade base oils which are ordinarily To illustrate theconditions which might be used, used in making up leaded lubricants aregenerit is found that at a temperature of 450 F. air ally characterizedby a Viscosity Index of 50 or may be bubbled through 3 gallons of oilata below, see Davis and Dean, Chemical and Metalrate of about 2 cu. ft.per hour for a time of lurgical Engineering 36-618 (1929) for adefiniapproximately 2%; hours. These conditions vary tion of the termViscosity Index. It is true considerably for different stocks. At theend of that asphalt containing residual oils such as black this timethe, other ingredients of the compound oils f m wh h r Viscosity n ex an50 are added and it is found that they are capable of have been used,but in all cases it is believed that remaining in the compound in astable form. The 30 whether distillate or residual, the base oils usedoxidation required is very mild and the chemical for the manufacture ofleaded lubricants are effect is not clearly known. While oxidation withordinarily characterized by Viscosity Indices beair or oxygen ispreferred other oxidizing agents low 80. Such oils are ordinarilyderived from may b u ed and it is not necessary to treat the naphthcnicor s a as ud s. a t fr m entire base oil, in fact only a portion need beso 35 the higher grade crudes such as are charactertreated and lateradded to the bulk, nor is it ized y e presence of wax. v necessary thatthe oil treated be a portion of The present invention relates to alubricating" the b t ck it e1f, i oil con ainin a hi h grade base whichis capable One of the constituents added to the'base is, 40 ofmaintaining the leaded c d in Stable of course, the lead soap or salt,and it is preferred o The base Oil used in the preshnt to use leadoleate,'which is the most widely availtionl Which is normally incapablef holding the able substance of the type. Other lead comleaded compoundin solution, is characterized by pounds, of course, maybe used, h as the1ead halving the Viscosity Index above 60 for distilsoaps of other fattyacids, stearate, palmitate, lat s a d above 80 for residual oils freefrom ricinoleate, resinate or other soap normally in- 45 a p nd m y h va V i y Index of 85, soluble in the high quality base. The lead soap isor even hi h r- It s p b e t p d stable, ordinarily added inproportionbelow about 10% light colored, clean and transparent oils containof t 1for le, it may be within the ing lead in effective quantities from oilsof Pennrange of 5 t 15%, r, as expressed in t rm of sylvania quality oreven better, such as the hydrot l h d, from 1 t 3%, 5o a d petroleumoils, a d the high grade oils A sulfurizing agent is also added to thecomproduced from solvent extraction processes. and pound to make theproduct effective in carrying even from synthetic oils produced bycondensaheavy loads The sulfurizing agent, is preferably tion of crackedor dehydrogenated wax, either of the "corrosive type, by which is meantthat it alone or condensed with aromatic hydrocarbons. is of the classof sulfur compound capable of disi low grade base oils are used in themanufacture interadjusted with ease so as to obtain products 20 Iinorganic sulfur compound, such as a sulfide;

coloring a bright copper strip when allowed to stand in the liquid forseveral hours at 212 1''. according to the general conditions of the A.S. T. M. corrosion test. It will be understood that non-corrosive sulfurcompounds may be used, but the corrosive type is so much preferable forthe present purposes that they should always be used where possible.Among the corrosive substances may be mentioned free sulfur andcompounds such as occur in the lower grade crudes rich in sulfur and itscompounds. Various synthetic materials may also be used particularlythose heavy enough not to be lost on heating, such as animal, vegetableand marine oils, sulfurized by the action of free sulfur at elevatedtemperatures, and the products of reaction of these materials with otherlmown sulfurizing agents. Synthetic materials may be produced by firsthalogenating fatty oils, fats and waxes, such as parafiin wax, and thenreacting the halogenated product or after dehalogenation, with anhydrosulfide, various polysulfides of alkali and alkaline earth metals.The reaction is readily accomplished at about 200 to 300 1?. and thesulfur gradually replaces the chlorine or other halogen.

The various sulfur compounds mentioned above are to be considered merelyas illustrations of the type of sulfurizing agents that may be employed.They are added to the oil so as to furnish about /2 to 5% of sulfur. Thesulfurizing agent may be added along with the lead compound or they maybe added separately, or the sulfur compound may be added to the oilprior to the mild oxidation treatment referred to above.

By the above methods it is possible to produce leaded oils of higherquality than are previously known, in that it is possible to use brightstocks and cylinder oils derived from the finest crude sources. It issometimes observed that the Viscosity Index of the finished compound isless than that of the base added and this is due to the effect of theparticular sulfur compound added, but ity y with smoothfriction-loadcurves.

The following examples are presented to illustrate the method ofproducing compounded oils according to the present invention and oftheir properties.

Example I The oil base selected was a heavy Pennsylvania cylinder oil,bright stock, having a viscosity of sec. Saybolt at 210 F. and 100 VI.Three gallons of this stock is mildly oxidized by blowing air thru whileat 450 F. for about 2% hours. The oil became slightly more viscous butdid not change substantially in appearance. To the oil is added 1% offlowers of sulfur and the oil was held at 400 for about half an hourwhile agitated. The product is then cooled and 10% of lead oleategradually incorporated.

The final product is of excellent apearance, only a few shades darkerthan the original oil.

When tested on the Almen machine, described in Automotive Industries11/19/32 vol. 67 No. 22, page 650, it was capable of carrying the fullload 'of 15,000 lbs. and the friction curve was smooth.

The final value of friction was 32 pound feet.

This oil was stable while similar oils made up with the untreated oilquickly settled out.

Example II A Pennsylvania steam refined cylinder oil was incorporatedwith 10% of lead oleate and the mixture blown with air at 450- F. forabout 2 hours, the rate being about the same as in the previous example.To the mixture is added 1% of sulfurized pine oil, so that the finalblend contained 3%'of corrosive sulfur.

, This oil was of good appearance and stable and on the Almen machineshowed about the same result as the oil of Example I.

The present invention is not to be limited by any theory of themechanism of the oxidation step or to any particular sulfur compound or.ingredient but only to the following claims.

I claim:

1; A method for producing improved lubricating oils comprising,subjecting a high quality lubricating oil base to mild oxidation toincrease its solvency for lead soaps and adding a lead soap and then asulfurizing agent uncombined with the lead of the lead soap. V

2. An improved lubricating oil comprising a lubricating oil which hasbeen mildly oxidized by blowing with an oxygen containing gas, freefromasphalt and characterized by a Viscosity Index above about 50, alead soap and a sulfurizing agent uncombined with the lead of the leadsoap.

3. An improved lubricating 011 comprising a base oil having a ViscosityIndex above 80 and a viscosity above about 50 seconds Saybolt at 210 F.,lead oleate and corrosive sulfur uncombined with lead of the lead soap,the base having been mildly oxidized while at about 450 F. with anoxygen containing gas only to such a degree as to render the finishedoil stable.

4. An improved lubricating oil comprising a base oil having a ViscosityIndex above about 80 and a viscosity-above about 100 seconds Saybolt at210 F., lead oleate in proportion of about 5 to 15%, and corrosivesulfur in proportion from about to 5% uncombined with the lead of thelead soap, the base oil being mildly oxidized at a temperature of theorder of 400 to 450 F, by blowing with an oxygen containing gas for atime sufilcient only to render the finished compound stable.

5. A method for producing improved lubricating oils comprising, mildlyoxidizing a lubricating oil of Viscosity Index above about 50 with airto such a degree as to maintain a lead soap in stable form, and addingto the oil 5 to 15% of a. lead soap and an organic sulfurizing agentuncombined with the lead of the lead soap in an amount suilicient tofurnish to 5% of sulphur.

6. A method for producing an improved high pressure bearing lubricatingoil comprising subjecting a petroleum lubricating oil base characterizedby a Viscosity Index above 80 to a mild oxidation treatment at atemperature of the order of 400 to 450 F. and for such time as to adaptit to maintain lead oleate in a stable form, addin to the oil 5 to 15%of lead oleate and to 5% of corrosive sulfur uncombined with the lead ofthe been mildly oxidized'at about 450 F. with an 8. Process ofmanufacturing an improved lubricating oil comprising adding to a baseoil having a Viscosity Index above about 80 and a viscosity above about100 seconds Saybolt at 210 F.,

which has been mildly oxidizedat a temperature of the order of 400 to450 F. by blowing with oxygen containing gas for a time suflicient onlyto render the finished oil stable, tree suliur in thefproportion ofabout $5 to 5% and holding the mixture for a prolonged period at areaction temperature to permit reaction between the sul- !ur and theoil, followed by the addition thereto 01 5 to 15% of lead oleate.

9. An improved lubricating 011 comprising a refined base oll distillatehaving a Viscosity Index above 60 which has been mildly oxidized byblowing with an oxygen containing gas, a lead soap soluble therein and aminor quantity of a substance selected from the class consisting of freesulfur and sulfur compounds of mineral, vegetable and animal oils. 1

10. A composition in accordance with claim 9 in which said lead soap isprment in the proportion of from 5 to 15%. 11. A composition inaccordance with claim 9 in which said lead soap is present in theproportion of from 5 to 15% and said substance selected from the classconsisting of free sulfur and sulfur compounds of mineral, vegetable'andanimal oils is present in an amount sufllcient to furnish to 5% ofsulfur.

12. An improved lubricating oilcomprising a residual oil free fromasphalts having a Viscosity Index above BO'which has been subjected tomild oxidation by blowing with an oxygen containing gas, a lead soap anda substance selected from the class consisting of tree sulfur and suliurcompounds of mineral, vegetable and animal oils.

solving therein a lead soap.

18.7A composition in accordance with claim 12 in which said lead soap ispresent in the tion of from 5 to 15%.

14. A composition in accordance with claim 12 in which said lead soap ispresent in the proportion 0! from 5 to 15% and saidsubstance selectedfrom the class consisting of tree sulfur and sulfur compounds ofmineral, vegetable and animal oils is present in an amount sufllcient tofurnish from V to 5% oi sulphur.

. 15. ,An improved stable composition comprising a refined base oilhaving a Viscosity Index above i 50,-which has been subjected to mildoxidation to increase the solvency of the oil for. lead soaps, said baseoils previous to oxidation being partial or non-solvents for lead soaps,and a lead soap dissolved therein.

16. Composition in accordance with claim 15 in which said lead soapdissolved therein is lead oleate in the proportion of from about 5 to15%.

17. Process for producing a stable lubricating oil lead soap compositioncomprising mildly oxidizing high grade lubricating oils which arepartial or non-solvents for lead soaps and are characterized byViscosity Indexes above about by blowing with an oxygen containing gas,and dislflaProcess in accordance with claim 17 in which said lead soapdissolved in the oxidized high grade lubricating oil is lead oleate inthe proportion from about 5 to 15%.

19. An improved stable composition comprising a refined base oil of theclass consisting of distillates having Viscosity Indexes above andresidual oils free from asphalts having Viscosity Indexes above whichhave been mildly oxidized by blowing with an oxygen containing gas, anda lead soap.

20. Composition in accordance with claim 19 in which said lead soap isfrom about 5 to 15% of lead oleate.

CHARLES B. KARNS.

